Professor Peter Tuthill from the University of Sydney's School of Physics reflects on his first encounter with Stephen Hawking at Cambridge University:

"Riding home late on our bicycles, my mate crashed into Hawking's wheelchair — which he drove around at some speed in those days and with no lights — on the quiet streets at the "backs" of the river Cam.

"This put both of them in hospital, and my friend on the front pages for all the wrong reasons.

"It was not until much later in my career after that I began to appreciate just why Hawking was such a titan in physics, but also more broadly in culture and modern society.

"While his contributions to deep questions in physics were profound, he also contributed to a wide array of extremely important contemporary debates and issues — things such as artificial intelligence, the building of a fair society, pitfalls and problems thrown up by disruptive technologies of tomorrow."

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